<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>EL算术表达式</title>

  </head>
  
  <body>
 	<%--运算 --%>
    ${3+5 }
    ${3*5 }
    <hr/>
    <%--判断 --%>
    ${true }
    ${false }
    ${3+5<10 }
    ${3>5 }
    ${3<5 }
    <% String name=""; pageContext.setAttribute("name",name); %>
    ${empty name }
    ${!empty name }
    <hr/>
    <%--逻辑运算 --%>
    <% String value=null; pageContext.setAttribute("value",value); %>
    ${3==5 }
    ${name=="" }
    <%-- 说明只有指定为null的对象才能用null判断，空字符串不为null --%>
    ${name==null }
    ${value==null }
    ${name==""&&3==3 }
    ${empty name!=true || 3+4<10 }
  </body>
</html>
